don't wait forever on dead lockfiles:
don't wait forever on dead lockfiles:

-      cmd_str = "lockfile ";
+      cmd_str = "lockfile -l20 -r5 ";

Retry at max 5 times (for 8 seconds) to get a lockfile, instead of trying
forever.

If the lockfile is 20 seconds old, delete it and wait another 16 seconds,
checking if it reappears and if not, obtain the lock.

svn path=/trunk/kdenetwork/kmail/; revision=171865

lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi